trying to get my 79 sa up and running smoothly. i have noticed that the rear leading plug wire does not fire everytime. i checked using a timing light. it does fire once every while but mostly is off. im guessing its the distributor but i had read about changing the 79 3 plug distributor over to the newer units. i have a 80 distributor but its a 6 wire connection. is there a conversion to swap them or should i just go ahead and change the cap and rotor on my 79 distributor?

also i did search and came up with only a few thing to electronic switch. im a noob to the 1st gen and there upgrades etc. any help is appreciated.

 

The 80 distributor needs an external control/ignitor box unique to just that year; it mounts on the left strut tower.

Your better bet, for a sustainable upgrade, is to get ahold of an 81/85 dizzy which has integral J109 ignitors. Easier to wire, less prone to misfire, simpler conversion all around. & there are a whole lot more of them around for replacement parts down the road.

Going from the 79 points ignition to anything newer will also require you to change your coils out; the 79 used low-voltage coils, all the other years used 12V coils. That's why the newer designs didn't require the ballast resistors.

Or, you could just figure out why you have a problem, and fix it. Points ignitions need maintenance but when kept in shape they do work just fine.

 

thanks for the info. ill probably chase the issue at hand. has to be something to do with the cap and rotor. i swapped the plug wire around just to eliminate that.

one thing i did notice is that when its on full decel. lets say reved up to 5k+ and just off the throttle i notice the spark works ok. those 2 vacuum lines and solenoids on the 79 distributor control any of that?

 

there are three extra 81-85 distributors in my garage right now. make an offer.

 

Try replacing your plugs. I just spent a day at the track trying to find a bad plug. Changed out everything ignition related. Had checked repeatedly for spark with the installed and used plugs, with mixed results. Finally swapped plugs (to a used set) as a last resort and the car ran like a dream. Very frustrating at the time.

Swapping the plugs is obviously quick. If it works great, if not you haven't wasted much time.

Carl

 

Are your points set correctly? I seem to recall that '79s had ballast resistors since they used 6 volt coils. Check the ballast resistor, I don't know what the value is but compare it to the one that works. If it is open, it's bad. If you put the coil wire against a ground, does it fire then? If so, could be bad cap or rotor.
Are your leading plugs firing at all?
1) Check point's gap and ensure that they are good.
2) Don't laugh but I've seen people put the wire to the points on the wrong side of the points so the wire was shorting all the time.
3) Check to see that you have voltage on the positive side of the coil.
4) Check to see if the leading wire (high voltage) from the leading coil sparks when held next to a ground. If so, you could have bad wires, dist cap or rotor or all three.
5) Check to make sure the mechanical advance on the dist is working.
6) If it fires from the coil and then fires from the dist wire, check your leading plugs to see if they are shorted.

I would find an 81-85 dist, get the coils that go with it and hook it up, it's really easy to do; if you have the manual, it will have the schematic on how that version is wired.